Television receiver screen and similar systems



June 12, 1951 P. M. s. TOULON TELEVISION RECEIVER SCREEN AND SIMILARSYSTEMS 2 Sheets-sheaf 1 Filed July 25, 1947 INVENTDR PIERRE MARIEGABRIEL TOLILON ATTORNEYS June 1951 P. M. s. TOULON f 2,555,858

TELEVISION RECEIVER SCREEN AND SIMILAR sYs'rEMs Filed July 25, 1947 V 2Sheets-Sheet 2 INVENTOR" PIERRE MARIE GABRIEL TOULON ATTORNEY PatentedJune 12,1951

TELEVISION RECEIVER SCREEN AND SIlWILAR SYSTEMS Pierre Marie GabrielToul'on, Neuilly-sur-Seine,

France, assignor to Products & Licensing Corporation, New York, N.- Y.,a corporation of Delaware Application July 25, 1947, Serial No. 763,664In France April11,.1943

Section 1, Public Law 690,-August 8, 1946 Fatent expires April 1, 1963 8Claims.

The present invention relates generally to systems in which the luminousintensity of each of a plurality of elements of' a surface is varied inaccordance with amplitude variations of an electrical signal, and findsparticular, though not exclusive, application in television receiverscreens.

It is a broad object of the present invention to provide a novel systemfor varying the luminous intensity of the elements of a surface inaccordance with variations of amplitude of an electrical signal.

It is a further object of the invention to provide as elements of avisible surface a plurality of fluorescent sub-areas which may beindividually excited in controllable degree in response to electricalsignals.

It is a further object of the invention to provide means forcontrollably determiningthe luminous intensity of. each of a pluralityof fluorescent elements of a surface by means of gas discharges to theelements of the surface, for time periods which are variable in responseto the amplitude of a signal.

It is another object of the invention to provide a novel gaseousconduction device in which ionized gaseous plasma is continuallygenerated, the plasma being effectively a cathode for a large number ofanodes and control electrodes, and wherein the anodes are fluorescent inresponse to discharge from the plasma to the anodes in response tosignals applied to the control electrodes.

It is still another object of the invention to provide a closed vesselwherein is located a plurality of fluorescent elements disposed side byside to form a composite surface therein, and wherein flow of ions tothe separate fluorescent elements, from anionized atmosphere providedwithin the vessel, is' controlled in response to control signals.

The above and still further objects, features and advantages of thepresent invention will become apparent upon consideration of the following detailed description of a specific embodiment thereof,especiallyrwhen taken in conjunction with the accompanying drawingswherein:

Figure 1 is a view taken in vertical section of a television receiverscreen and associated control elements, arranged in accordance with thepresent invention;

Figure 2 provides graph of current flow during.

predetermined time intervals, as established in response to controlsignals, and further illustrat'es luminous intensity accomplished inresponse to each of the signals; and

Figure 3 is a schematic view corresponding with the structureof Figurel, and illustrating in conventionalizedmanner the circuit elements andstructure of the electronic tube of Figure 1-.

Identical components in Figures 1 and 3 are identified by the samenumerals ofreference. There is provided an enclosed bulb I, within whichis locateda block fabricated of refractory material which separates bulbI into two independent compartments 3 and 4-, electrically isolated fromone another, in a manner which will become evident as the descriptionproceeds.

In the compartment 3 is provided a cathode 5 and a cooperating anode 9,the anode 9 being supplied with voltage, throu-gha resistance It, by

.a source of positive anode potential II, conventiona'lly illustrated asa battery, this potential being suliici'ently high so that gas which iscontained within the compartment 3 is maintained in ionized conditionthroughout the compartment 3.

In the compartment 4 is provided acathode 6, which is maintainedenergized by a suitable source ofpotential, and an anode I2 which ismaintained at a normal negative potential with respect to the cathode 6There is applied to the anode I2 a positively going saw-tooth voltage.froma source 26; There is further provided a mentd by means of grids 8,which are similarly connected via protectivere'sistan'ce I6 to asourceof negative potential H. The grids I and 8 ac-' cordingly operate toisolate the chambers 3 and 4, respectively, from one: another in respectto spread of ionization, so that gas in one of the chambers may beionized when the gas in the other chamber is not ionized, and so thatthe intensity of the ionization in either of the chambers will'tnotberefiected as a, change in ionization in: the other chamber.

Similarly A visible screen is provided in compartment 3, which isconstituted of a multiplicity of elementary anodes H, M, ii, etc. Eachof the anode elements is covered with fluorescent material, so as tobecome highly luminous under the impact of ions striking it, these ionsderiving from the ionized gaseous plasma contained in compartment 3.

It will be clear from the preceding description that in each ofcompartments 3 and 4 is formed a virtual ionic cathode, in the form ofionized gaseous plasma, which acts with respect to the anodes in thecompartments, much as does a conventional heated cathode. It will beheated, however, that in compartment 3, since no control electrode isprovided, and since a constant voltage exists between anode 9 andcathode 5, that a constant ionization of the gas contained incompartment 3 is maintained. Therefore, with respect to anode 51, I1,I?" the gaseous plasma provides essentially a cathode of constantemissive power, which is available for any one of the anodes at anytime.

In chamber 4, on the other hand, this is not true, since anode I2 issupplied with saw-tooth voltage from a saw-tooth voltage generator 26,and since a control electrode I3 is provided, which is subjected tosignal voltages of variable amplitude, applied to terminals M.

Considering first the operation which takes place in compartment 4, itwill be evident that the anode l2 rises positively in voltage withrespect to the cathode 6 at a constant rate, and that for any givenvoltage applied to the control electrode l3 ionization will take placeonly after the anode i2 has reached some predetermined positive value,and once it has taken place will continue until anode potential isreduced to zero. The positive value of anode voltage at which ionizationinitiates in turn depends upon the magnitude of the control voltageapplied to control electrode i3. Accordingly, for each cycle of sawtoothvoltage provided by saw-tooth generator 25 ionization takes place inchamber 4 for a period of time which is determined by the magnitude ofthe signal applied to control electrode l3, and for the remaining timethe gas contained in chamber M is deionized.

Reference is now made to Figure 2 oi the accompanying drawings, for afurther explanation of the phenomena explained in the previousparagraph.

Figure 2 shows saw-tooth voltages 3|, 3|, 3|", as supplied by saw-toothvoltage generator 26. Voltages 32, 32 and 32" represent signal amplitudesupplied to the control electrode l3. It will be noted that the signal32, which is relatively small in amplitude, permits ionization of thegas in compartment 4 when the anode voltage [2 has reached a relativelysmall positive value as at 33. The intermediate signal value 32' delaysionization until the saw-tooth voltage 3! has attained a magnitude 33.On the other hand, the still greater signal amplitude 32" delaysionization until the saw-tooth voltage 3| has attained a value 33".Accordingly, the total duration of ionization in the compartment 3, foreach sawtooth cycle, is a function of the signal amplitude existing,during the saw-tooth cycle, on the control electrode i3, but themagnitude of ionization, as is well understood, is of constant amount.The eiTect of the signal voltage applied to control electrode 53 viaterminals M is, then, to establish in the compartment 4 a series ofpulses of ionization, which are of constant amplitude, butrof variableduration, and by virtue of such variable durations represent the signalapplied to the terminals M. The total durations of these ionizationpulses is represented in Figure 2 by the shaded areas 34, 34, and 34"respectively in response to control voltage amplitudes 32, 32' and 32".

There is provided in the compartment 4 a, p1urality of anodes 25, 25,25" etc., with respect to which the gaseous ionized plasma in thecompartment for-ms a cathode, and particularly a cathode which is activeand inactive in alternation, the active periods being of variableduration in accordance with the amplitude of the input signal at theterminals M. Applied to the anodes 25, 25, and 25 is a series ofpositive pulses, which derive from the source 2 3 in Figure 1,represented in Figure 3 as i2 i, these pulses being applied to theanodes 25, 25, 25 ia condensers 23, 23, 23", respectively, in timesequence. Voltage peaks are all of the same amplitude, and follow eachother at equal intervals of time, so that the anodes '25, 25, 25' areenergized in sequence for predetermined times. Current accordingly flowsfrom the gaseous plasma in the compartment 6 to the anodes 25, 25, 25 inscquence, but onl for the times when the plasma is ionized, since atother times no cathode exists from which the anodes 25, 25, 25" may drawcurrent. Accordingly, current flows in the separate anode circuits !22,E22, I22" (Figure 3) only when these anodes are supplied with positivevoltage from the source i2 5, which occurs in sequence, and during eachanode energization only for the time during which the gaseous plasma isenergized, and consequently foratimewhich is inversely proportional tothe amplitude of the impressed signal at the terminals M.

Current flow from the anodes 25, 25', 25" to cathode 6 takes place fromcondensers 3t, 35, 3%". via resistors 22, 22, 22", since thesecondensers tend to assume the voltages of the associated anodes 25, 25',25" respectively, and ac cordingly, these condensers become dischargedto a voltage which is proportional to the durations of the separatepulses of ionization in the compartment 4. The voltage on the condensers35, 36, 35 respectively are inversely proportional, then, to theamplitudes of the signals occuring during the times when the condensersare being discharged.

The condensers 36, 36', 3%" are connected directly to control electrodes2|, 2i, 2 I which are respectively associated with anodes H, H, ii, allof which have for their cathode the continuously ionized gaseous plasmain the compartment 3, and all of which are normally at the potential ofcathode 5.

There is applied to the anodes ii, i 7', i? from a source of saw-toothvoltage 26, in parallel, a positively going saw-tooth voltage whichtends to effect a discharge from the ionized plasma to the anoderespectively. The discharge, however. can take place only at times inthe positive sawtooth voltage cycle which is determined by the potentialon the control electrodes 2!, 2i, 2!". These latter are sequentially ata potential positive relative to their unmodulated value by an amountinversely proportional to the signal in put applied to the terminalslvi. At the same time the total period of discharge of condensers 3%,35, 38 to the anodes ii, i, I? is inversely proportional to the signalson the control electrodes 2!, 2 i 2 i as will be evident from Figure 2of the drawings. From this figure, it will be evident that a largerinput signal permits transfer of current to an anode 25, 25" during ashorter interval of time. Accordingly, the total time during whichcurrent flow occurs with respect to any of anodes H, H, ll" becomesdirectly proportional to the amplitude of the signal applied to theinput terminals M. The total illumination produced on any one of theanodes H, ll, I1", by reasonof bombardment Of the fluorescent coatingthereof by the ionized gas, is a function of the total time during whichthe bombardment takes place, and, accordingly, an observer of thefluorescent anodes H, H, H, will perceive at each of these elements anintensity of illumination which is proportional to the amplitude of thesignal applied by the terminals M, during the time when the element isin circuit in response to voltages supplied by the commutation voltagesource E24.

In order to effect ice-charge of the condensers 36, 36, lit to theproper negative values in the intervals intervening between signalapplication thereto, so that each condenser may be ready for asucceeding discharge, representative of a succeeding portion of theinput signal, resort is had to a system of the character of thatdescribed in my U. S. Patent application Serial #739,153, entitledSystem for Controlling the Flow of Successive Electrical Impulses in aChannel, filed April 3, 1947, and issued February 13, 1951 as Patent No.2 $341,133. Essentially, this application discloses a device whichprovides a series of identical voltages having successive constant phasedifference with respect to one another, the voltages having rectangularwave shapes, as shown at I29 in Figure 3, and the voltages deriving froma source 29, and being applied to the condensers 36, 36, 36", insuccession, synchronization between the source I24 and the source 29being such that each condenser is raised in potential in response to avoltage provided by the source 52d, and then lowered in potential inresponse to a voltage provided by the source 129, the total time periodbetween raising and lowering being that established by one cycle ofsawtooth voltage as provided by saw-tooth source 26. Once any condenserhas been lowered in potential to its normal value, it is so maintainedby potential source 30.

The elements 31, illustrated in Figure 3 of the drawings, representcapacitors, which may be utilized to transfer voltages from the sourcesI24 and I29 through the glass envelope of the tube I.

Briefly described, then, and in accordance with the present invention, asignal is applied to the terminals M, establishing a variable voltage onthe control electrode 53. The anode I2 is raised from anegative'potential, or from a zero potential if desired, in a positivedirection in response to saw-tooth voltage provided by the saw-toothgenerator 26. When the saw-tooth voltage attains a value determined bythe then instantaneous value of the signal applied to control electrodeI3, the gas in compartment Q ionizes. Accordingly, ionization takesplace in the form of pulses having durations established by theamplitude of the input signal at the terminals M. Positive voltages areapplied from source IN to the anodes 25, 25, 25", in sequence, and insynchronism with the saw-tooth voltage provided by the source 265.During the time that any one of anodes 25, 25, 25 is selectivelypositively polarized in response to voltage from the source I24, and thegas in compartment t is simultaneously ionized in response to voltageapplied to the assesses anode I2 and the control electrode l3, currentflows to the anode 25 and to the selected ones of the anodes 25, 25,25", which then attains a voltage approximately that of the cathode 6.

Condensers 36, 36, 36 are normally maintained at a fixed negativepotential by a potential source 38, and maintain control electrodes 2!,2!, 2!", respectively, at the same negative potentials. There is appliedto anodes ll, H, H", associated respectively with control electrodes 2!,2!, 2!", a saw-tooth voltage from a source 28, this voltage beingpositive going, and consequently capable of establishing flow of currentbetween the anodes and ionized gaseous plasma in the compartment 3,should the relation between the voltages en any given anode and controlelectrode be suitable for this purpose. Normally the negative bias onthe control electrodes 2i, 2!, 2!, is sufiiciently high to prevent suchaction. However, when any one of anodes 25, 25, 25" discharges throughthe ionized gaseous plasma in compartment 4, voltage on thecorresponding one of condensers 1'35, 35", as" is raised in a positivedirection, so that efiectively negative bias is removed from thecorresponding control electrodes El, 22', 2i. The total discharge whichtakes place from the selected condenser is determined by the totalperiod during which ionization occurs in compartment 4, since thedischarge of the condenser takes place through an associated resistor,as 22, 22', 22", only during such time. Accordingly, the selectedcondenser, of condensers 35, 3t, eventually attains a potential morepositive than its normal potential, and which represents the total timeof ionization of the gas in compartment 4 during one cycle of saw-toothvoltage supplied by source 26, and consequently also represents theintensity of the signal applied to input terminals M. When a selectedcontrol electrode 2|, 2|, 2i" attains a more positive potential than isnormal, current flow from the ionized plasma in compartment 3, to acorresponding anode, may take place at a suitable time during a cycle ofsaw-tooth voltage from the source 20. Accordingly, these current flowstake place for periods representative of the amplitude of the signalapplied to terminals M. The effect on the observer of any one offluorescent anodes ll, I7, I?" is to average out the total illuminationon the anode, and accordingly the effect of illumination of the anoderepresents the amplitude of the input signal at terminals M.

While I have described and illustrated one specific embodiment of myinvention, it will be evident to those skilled in the art that variousmodifications thereof may be resorted to without departing from the truespirit and scope of the invention.

What I claim is:

1. In combination, an electronic tube having an envelope containing gas,a heated cathode and an anode in said envelope, means for maintaining apositive potential between said anode and said cathode of sufficientmagnitude to maintain said gas ionized, a plurality of furtherfluorescent anodes immersed in said gas, a separate control electrodeadjacent each of said anodes, means biasing said electrodes normally toprevent current fiow to said anode from said ionized gas, a source ofpositive saw-tooth voltage, means for applying said saw-tooth voltage tosaid plurality of fluorescent anodes, current flowing to each of saidanodes during said voltage upon attaininent of a value of said voltagedetermined by the bias or the adjacent control electrode.

2. A system comprising, a closed vessel, a plurality of fluorescentanodes disposed in said vessel to form substantially a compositefluorescent surface therein, a gaseous atmosphere in said vessel, meansionizing said gaseous atmosphere, means for sequentially establishing aflow of gaseous ions from the ionized gaseous atmosphere to saidfluorescent anodes in succession, a source of control signal, and meansresponsive to said control signal for controlling the duration of theflow of gaseous ions from the ionized gaseous atmosphere to each of saidanodes in accordance with the amplitude of said control signal.

3. The system in accordance with claim 2 wherein said means responsiveto said control signal includes a control electrode associated with eachof said anodes, and means for applying said control signal to saidcontrol grids in sequence.

4. A system comprising a closed vessel, a gaseous atmosphere in saidclosed vessel, means for establishing ionization in said gaseousatmosphere along a predetermined path in said gaseous atmosphere, and apluralit of fluorescent anodes disposed in a path parallel to butdisplaced from said predetermined path, a separate control electrodeinterposed between said predetermined path and each of said anodes, andmeans for applying operating potentials to said control electrodes andto said anodes.

5. The combination in accordance with claim 4 wherein a saw-toothvoltage is commonly applied to all said anodes, and wherein positivelygoing control signal is applied to said control electrodes in sequence,and means normally biasing all said control electrodes to cut-off.

6. An electronic system for receiving electric 8 signals and translatingsaid signal into a visual representation, comprising, a plurality ofconducting fluorescent elements disposed side by side to constitute acomposite surface inside said bulb, means for forming an ionizedatmosphere adjacent said composite surface, means for generating aperiodic saw-tooth voltage, means for applying said saw-tooth voltagesimultaneously in positive polarity to all said elements simultaneously,a separate control grid interposed between each of said elements andsaid ionized atmosphere, a plurality of normally blocked signaltransmitting channels having each an output circuit, means connecting aseparate one of said output circuits to each of said control electrodes,each of said channels comprising an input circuit, means for applyingsaid electric signal to said input circuit, and a source of voltage forunblocking said channels in succession.

'7. The combination in accordance with claim 6 wherein said source ofvoltage comprises means for generating sharp voltage pulses in saidchannels in sequence.

8. The combination in accordance with claim 'I wherein is furtherprovided means reblocking said channels in sequence and withpredetermined time delays following said sharp voltage pulses.

PIERRE MARIE GABRIEL TOULON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 17,712 Schmierer June 24,1930 2,110,172 Phinney Mar. 8, 1938

